XML 41 R97.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Condensed Financial Information of Registrant Condensed Financial Information of Registrant (Narratives) (Details) (USD $) | 0 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Jul. 02, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 03, 2014
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |
Proceeds from Dividends Received |  | $ 225,000,000 us-gaap_ProceedsFromDividendsReceived | $ 120,000,000 us-gaap_ProceedsFromDividendsReceived | $ 145,000,000 us-gaap_ProceedsFromDividendsReceived |
Capital contributions to subsidiaries |  | 125,000 mcy_CapitalContributionsToSubsidiaries | 125,000 mcy_CapitalContributionsToSubsidiaries | 125,000 mcy_CapitalContributionsToSubsidiaries |
Credit facility amount |  | 150,000,000 us-gaap_LineOfCreditFacilityAmountOutstanding |  |  |
Total borrowing guaranteed |  | 20,000,000 us-gaap_SecuredDebt | 20,000,000 us-gaap_SecuredDebt |  |
Loan maximum borrowing capacity | 200,000,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity |  |  |  |
Revolving credit facility term | 5 years |  |  |  |
Mcc [Member] |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |
Credit facility amount |  | 120,000,000 us-gaap_LineOfCreditFacilityAmountOutstanding / dei_LegalEntityAxis = mcy_MccMember |  |  |
Bank loan |  | 20,000,000 us-gaap_LoansPayableToBank / dei_LegalEntityAxis = mcy_MccMember |  |  |
Municipal bonds, fair value |  | 181,000,000 us-gaap_MunicipalDebtSecuritiesAtCarryingValue / dei_LegalEntityAxis = mcy_MccMember |  |  |
Total borrowing guaranteed |  | 140,000,000 us-gaap_SecuredDebt / dei_LegalEntityAxis = mcy_MccMember |  |  |
Revolving Credit Facility [Member] |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |
Credit facility amount |  | 150,000,000 us-gaap_LineOfCreditFacilityAmountOutstanding / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember |  |  |
Loan maximum borrowing capacity | $ 200,000,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember |  |  |  | $ 250,000,000 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember
Revolving credit facility term | 5 years |  |  |  |

X
- Definition Capital contributions to subsidiaries. + References No definition available. + Details
Name: | mcy_CapitalContributionsToSubsidiaries
Namespace Prefix: | mcy_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount borrowed under the credit facility as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityAmountOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of loans from a bank with maturities initially due after one year or beyond the normal operating cycle if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
Name: | us-gaap_LoansPayableToBank
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Bonds or similar securities issued by state, city, or local governments or the agencies operated by state, city, or local governments which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
Name: | us-gaap_MunicipalDebtSecuritiesAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Dividends received on equity and other investments during the current period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585 + Details
Name: | us-gaap_ProceedsFromDividendsReceived
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_SecuredDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=mcy_MccMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |